The city of Pergamum is attacked by the Galatians (Celts who have settled in central Anatolia) because the leader of Pergamum, Attalus I Soter, has refused to pay them the customary tribute. Attalus crushes his enemy in a battle outside the walls of his city and to mark the success he takes the title of king and the name Soter.

King Agron of Illyria dies. Pinnes, the son of Agron and Agron's first wife Triteuta, officially succeeds his father as king, but the kingdom is effectively ruled by Agron's second wife, Queen Teuta (Tefta), who expels the Greeks from the Illyrian coast and then launches Illyrian pirate ships into the Ionian Sea, preying on Roman shipping. She continues her husband's policy of attacking cities on the west coast of Greece and practising large-scale piracy in the Adriatic and Ionian Seas.

With Roman merchants being killed by the Illyrian pirates, envoys are sent by Rome to Illyria. After the Roman ambassador lucius Coruncanius and the Issaean ambassador Cleemporus are murdered at sea by Illyrian soldiers after causing offence to Queen Teuta, Roman forces occupy the island of Corcyra with the aim of humbling Teuta.